The present invention relates to a retractable cover for covering an opening in a substantially flat surface. In more detail, the present invention relates to a retractable cover for closing an opening such as the opening to an oil change pit in the floor of an automobile or other vehicle repair shop in which the space for the stack of the cover when retracted is limited.
Many vehicle repair shops are provided with openings, or pits, in the floor to facilitate access to the underside of the vehicle. As a result of the recent growth in the number of self-service gasoline stations and the large number of consumers who are pumping their own gas, there has been a large increase in the number of businesses which market services such as oil changes and vehicle lubrication. Such business may have several service bays, each provided with a pit in the floor. Those pits are two to four feet wide and may be twenty feet or longer in length. The vehicle is driven into the service bay straddling the pit, which is deep enough to allow a mechanic to stand erect underneath the automobile. Such pits are also found in motor and service pool facilitites and even between the rails of railroad tracks running through diesel locomotive service facilities.
No matter what the location, such pits are a substantial safety hazard. Such large openings in a substantially flat floor are a safety hazard which have, unfortunately, been the cause of many falls and injuries. These pits which are surrounded by a raised, metal border, such as those which are commonly found in oil change service businesses, are particularly dangerous because that raised metal border projects upwardly from the floor from one to three inches and represents an obstacle over which persons can trip, causing them to fall into the pit. Such pits are provided with that barrier to serve as a guide and bumper rail to warn drivers of the closeness of their vehicle to the edge of the pit as the vehicle is positioned over the pit for servicing.
The safety hazard presented by such pits, therefore, creates a need for a cover for such pits which can be retracted to allow the mechanic to either enter the pit or service a vehicle, and which can be extended to cover the pit once the service has been accomplished to remove or reduce the hazard presented by the pit. It is, therefore, an object of the present invention to provide such a cover, thereby preventing injuries to the mechanics and customers of such businesses.
Providing such a cover is made difficult, however, by the limited vertical space which is available in such installations. In actual practice, as little as three inches of vertical space is available between the bottom of the lowest vehicle which is serviced from such pits and the top of the waste oil collection pan with which the pit is supplied. It is desirable to raise that pan as high as possible to decrease the spillage of oil from the vehicle when the drain plug is removed, hence the vertical space limitation. That vertical space limitation, of course, inconsistent with the object of providing a safety cover for such pits which is strong enough to withstand the force of, for instance, a 250 pound service technician who falls on the cover because, as a general rule, each panel of the cover needs to be thick enough to provide the necessary rigidity. It is, therefore, also an object of the present invention to provide a retractable cover for an opening which is of particular use in installations in which the vertical space which is available is limited yet the cover must be rigid enough to withstand the impact of substantial force anywhere along the length of the cover.
It is another object of the present invention to provide a retractable cover for an opening in a substantially flat surface which is adaptable for use in a number of applications, for instance, as the trash racks of a hydropower installation or the entrance to a sewer grating or ventilation shaft. Such installations require the ability to retract or remove the cover at relatively frequent intervals for service and/or cleaning. A light weight, retractable cover which can easily be removed from such openings at frequent intervals greatly facilitates such operations.
Other uses, objects, and advantages of the present invention will be clear to those skilled in the art from the following description of the presently preferred embodiments of the present invention.